mutt-sigtrace is a wrapper for sigtrace to display signature paths from you to the key
which signed an email, automatically, in mutt. It adds the bolded part of the following when
viewing a signed email:

This file is probably called .gpg.rc, located in your home directory, and
loaded by "source ~/.gpg.rc" in your .muttrc.

Download mutt-sigtrace.pl to your home
directory, and make it executable (chmod u+x mutt-sigtrace). Now modify the
"set pgp_decode_command" and "set pgp_verify_command" lines by adding
"~/mutt-sigtrace YourID " to the beginning of their values, like so: